1. Field of the Invention
The present disclosure relates to sensors, and more particularly to inductive contactless sensors for measuring rotational speed.
2. Description of Related Art
Induction-based sensor technology uses sensing coils that are made of copper traces printed on electronic printed circuit board. This type of sensor is capable of measuring the relative position between a sensing printed circuit and a position target without being in physical contact with it. This technology is outlined for various applications in U.S. Pat. Nos. 6,534,970 and 8,129,985, each of which is incorporated by reference in its entirety. This type of technology has been widely used for position sensing, but has not been often used to measure speed of a target.
Various sensor assemblies for measuring the rotational speed of an object are known in the art. In many conventional applications, the sensor system is either positioned in contact with the object to be measured, or is a non-contact system, e.g., with electromagnetic wound coils, magnet systems, or optical solutions. These systems have many disadvantages, including being expensive, bulky, heavy, or sensitive to noise introduced in harsh operating environments such as those having mechanical vibrations and variable temperatures. These systems are also subject to other sources of error including noise and signal interference associated with mounting analog signals around other sources of electromagnetic interference.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is a need in the art for implementing less expensive, smaller sized, and lighter weight devices with higher accuracy and better linearity for measuring rotational speed and communicating the output in a more robust digital signal that is more resistant to noise and electromagnetic interference. There is also a need to use less complex means to adopt advanced networking and wireless communication systems. The present disclosure provides a solution for such implementation.